Typewriting machine



Sept. :8, 192a, 1,684,820 w. A. DOBSON TYPEWRITING mdamr:

Filed Oct; 20. 1925 2 Sheets-Sheet 1 Affazwey Sept. 18, 1928. 1,684,820

W. A. DOBSON TYPEWRITING MACHINE Filed Oct. 20, 1925 2 Sheets-Sheet 2 FfiflA/T ELEVATION Patented Sept. 18, 1928.

* UNITED STATES 1,6843% PATENT OFFICE.

WILLIAM A. DOBSON, OF BRIDGETORT, CONNECTICUT, ASSIGNOR TO THE UNLERWOOD ELLIOTT FISHER COMPANY, OF NEW YORK, N. Y., .A. CORPORATION OF DELA- WARE.

TYPEWRITING MACHINE.

Application filed October '20, 1925. Serial No. 63,605.

associated escapement-pinion that varies in,

different machines due to the variations in a manufactured product and hence the subse quent assembly of a back-spacing mechanism to engage with the teeth of the escapementwheel or with the teeth of the escapement-pinion requires individual adjustment of a backspace pawl to. properly time the engagement of the pawl to a'tooth-position and ensure positive coaetion thereof from a limited keyaction. As these coacting parts are usually carbonized, the pawl frequently requires stoning or grinding, which is impossible in a congested assembly without first removing'the pawl. One feature of the present invention provides a carrier for the back-space pawl that has a one-way connection to the back space key and a single spring-connection to the frame, so that by the simple operation of unhooking one end of the spring,the carrier and its pawl may be easily and quickly removed from the coacting parts and as quickly replaced in operative position. To this endthe back-space pawl-carrieri s arrangedto slip over the free end of the escapement-pinion to rotate upon the faces of the teeth thereof and held in operative relation thereto by a novel arrangement of a spring that both restores the carrier to normal position against a stop andresiliently prevents undue sidedispiacement ofthe carrier upon the pinion, the latter effect being assisted by the angle of inclination of the assembled pinion. The'c'arricr is further formed with a stop-arm to establish a normal position therefor, a stop for the pawl, and a tension spring for the pawl, all forming a unit of assembly that is removable from the pinion as a unit so that the several stop-members and pawl may be individually fitted to the pre-assembled carriage-feeding devices.

\Vhen the carriage-feeding devices and the back-space pawl are assembled upon the casetive connection betweenthe back-space key andthe back-spacepawl and substitute therefora one-way or broken connection to the pawl which is effective to back-space the car riage and prevent overthrow thereof by a novel interlocking of the coacting parts. The pawl includes a lateral stud engageable with a long straight face on an upright frame slidable upon the machine-frame at each depression of the back-space key. The stud in shifting with the case-shift frame rides up or down against said arm and a fine, close adjustment of the back-space pawl will be uniformly the same at either case-shift position of the carriage. The'key-actuated arm is operative to first swing the pawl into interlocking engagement between two adjacent teeth, of the escapement-pinion and the continued movement of said arm causes the carrier, the pawl and the pinion to rotate in unison and any inertia from the carriagemovement will be resisted by the interlock of the pawl backed up by the key-pressed upright arm. v 7

All back-spacing mechanisms require some form of a back stop to hold the carriage in its back-spaced position; In the present invention, the stepping dog that normally holds an escapement tooth is so formed as to permit the tooth shifted by the back-space pawl to cam the dogsidewise and subsequently snap under the face of the tooth and thus eliminate a special back stop for this purpose.

A further feature of the invention is to providea simple, durable, light, compact and inexpensive assembly of the parts to meet the requirements of portable typewriter I manufacture. Other features and advantages will herein after appear. Y I In the accompanying drawings, Figurel is a perspective view, in elevation, showing the backspace key operatively connected to the back-space pawl.

Figure 2 is a cross-sectionalview,,in'elevation, through the carriage and the escapement mechanism of an Underwood portable typewriting machine. 7 a I Figure 3 is a front view, in elevation, of the escapement mechanism showing the backspacing pawl in its normal position.

Figure 4 is a plan view of the mechanism illustrated in F igure 3. Figure 51s an operational engagement with the pinion preparatory to rotating the pinion.

Figure 6 is a view similar to Figure 5, showing the back-space pawl at the end of its throw.

Figure 7 is a view similar to Figure 2, show- 7 ing the platen in upper-case position, where- "to the carriage by means of a rack 19 engagasin said Figure 2 it was shown in lower-case position. v

Figures 8 andf) are, respectively, side and plan views of the eseapement-wheel, pinion and dogs, showing the passage of a tooth 'between the dogs under a back-spacing operation. p

This invention is applied to an Underwood portable typewriter which has a carriage 10, arranged for letter-space travel upon rails 11 having anti-friction balls 12. Said carriagecarries a platen 13 journaledin the end plates of the carriage upon an axle 14 and is urged in one direction by means of a spring-drum 15around which there is wound a tape 16, the end of which is secured to a stud 17 on the carriage. y

In my pending application, Serial No.

63,370, filed October 19, 1925, an escapement mechanism is shown operatively connected ing witha pinion 20 forming an integral part of an escapement-wheel 21, rotatably mounted on a stud 22 fast to a plate 23 whichin turn a is secured to the back frame 24 of the machine 40 i by means of screws 25. The rack is mounted on arms pivoted at the carriage ends and may be disconnected from the pinion in the usual manner. 7

The escapement disclosed in said application has a pair of dog-rockers 26 and 27 rock ably. mounted upon a pivot 28, the rockers being vibrated by means of the usual universal bar.

Each rocker has a dog 29 and 30 respectively, the dog 30 normally holding some tooth 31 of the ,escapement-wheel 21 but releasing the tooth 31 when the rocker.

26 and its dog 29 are vibrated to intercept the same toothto initiate a letter-space movement for the carriage.

Sometimes it may be desirable to movethe carriage back one space against-the tension of the tape 16 which normally urges the carriage to travel in letter-space direction. To this end, there is provided a key 32, near the keyboard of the machine, securedto a'keylever 33, rockably mounted upon a stud'34, which is in turn secured to a side frame 35 by means of a serew36. The lever 33 is laterally positioned between collars 37 secured to the stud 34, and is guided at the front in aslot front view, elevatlon, oi the escapement mechanism, showing the back spaclng pawl swung 111130 38 cut in a front comb-piece :39, which may i comprises a rear extension 42 of said lever 33, f upon which there is pivotally mounted a link V 43 by means of a stud 44. Said link 43 extends rcarwardlyand 1s-connected,by means of a screw 45, to a bell-crank 46, pivotally mounted upon a shoulderstud 47 secured to bracket 48 which in turn is secured to the side frame 35 by means of screws 49. The bellcrank has a rearwardlyrextending ar1n50 and carries a link 51 pivotall which link extends towarc the center of the machine and terminates with an upwardlyezztcnding arm 53 designed to engage a stud 69 carried by saidpawl. By depressing the mounted at 52,

key 32, the link 51 is causedto slide on a guide 54, which engages within an elongated slot 55 insai'd link. The guide'is secured to a bracket 56,which is'in turnsecured to a cross rail 57 by means of'screws 58, the cross-rail" being fast to the side frame 35 by means of screws 59. I

Upon depressing the key 32, the link 51 will be slid from a position shown in Figure 3 to that shown in'Figure 5, thereby swinging the pawl 41 into engagementwith the pinion 20. Said pawl 41 is pivotally mounted upon a stud 60, secured to a plate or carrier 61 which in turn is pivotally mounted over the teeth of the pinion 20." The earrieris held in normal position,-as shown 'inFigures 3 and 5, by means of a spring 62 actuating between a forwardly-extending tab '63 oi" the plate 23 and an extension 64 of the'carrier 61; Said extension 64 serves alsoas a means for positioning the carrier 61, which is held against a stop 65 forming an integral part of the plate 23. Since the pawl is normally held out of engagement with the pinion' 20 by a spring 66, which is lighterthanthe spring 62 holding the carrier 61 in its normal posi i ti'on, it will be seen that, upon sliding the link 51, the pawl will be first swung into engage ment with the teeth of thepinion, and then the carrier will be swung with the pinion. In order that the pawl may be normally held away from the pinion, the same may beprovided' with an extension 67, held against'a stop 68 forming an integral part of the carrier 61. g p

In the particular type of case-shift machine with which this invention is illustrated, the escapement mechanism is raised as a unit when the platen iselevated to receive typing lilo Hit

in upper case, whereas the link 51 and all allied linkage, includingthe back-space key, are operatively mounted upon the machine frame. It will be readily understood, therefore, that mechanism must be provided to connect the link 51 and the pawl 41 ina mannor to permit an up-and-down movement of the pawl, while maintaining operating relationship between the pawl and the link. To this end, the arm 53 of said link 51 is made long enough to engage the stud 69 in both positions of the carriage shift, as shown in Figures 2 and 7. i i i It will be noted that, owing to the manner in which the escapeinent mechanism operates,

it is possible to rotate the escapement-wheel 21 backwardly, said escapement-wheel hav ing backed-off teeth at 70 on the side of the I wheel 21, which teeth engage with the beveled under face of the stepping dog 30 held in engagement with the teeth by means of a spring 71'. I

The key-lever 33 and its associated linkage are held in their normal position by means of a spring 72, having one end secured to a downwardly-extending arm 73 forming an.v

integral part of said key-lever, the other end being secured to a spring-stud 74 fast to a lug 75, extending inwardly from the side frame 35.

It will be noted that the escapement-pinion 20 is open on the forward end, permitting the carrier 61 and its back-space pawl 41 to be adjusted over the end thereof to rotate upon the teeth of the pinion, and that the pinion rotates within the assembled'carrier in letter-spacing; that the carrier is held n operative position upon the pinion by the tension of a spring 62; that the carrier, with the pawl 11 and its spring 66 assembled thereto, may be removed from the pinion after first unhooking one end of the spring 62, thus enabling the assembler to quickly and individually adjust the extension 67 to" the stop 68, adjust the extension 64 to the stop 65, adjust the tension of the spring 66 or adjust the tooth of the pawl 41 to the teeth of the pinion by stoning or grinding, all ad'- justments that would be difficult to make if these parts were permanently assembled to the carriage-frame; and that the back-spacing unit has no positive, pivotal connection to the key-actuated link, to interfere with the removal orassembly of the unit or interfere with the case-shifting movement of the unit with the carriage.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. The combination with. a typew'ri'ting machine having a carriage arranged for letter-space travel, a carriage-feeding mechanism therefor, and pinion-and-rack arrangement for operatively connecting the carriage and the carriage-feeding mechanism, of means 'for'back spacing the carriage, said rotate with the pinion in a direction opposite.

to the letter-space rotation of the carriage, and means actuated by said key and operatively connecting said pawl.

2. The combination with a typewriting machine having a case-shiftable carriage ar ranged for letter-space travel, a carriagefeeding mechanism therefor, and a pinionand-rack arrangement for operatively con-i necting the carriage and the carriage-feedin v i b mechanism, of means controlled by a key and shiftable with the carriage for backspacing the carriage, said means including a carrier rotatably mounted upon the pinion, a normally inoperative pawl pivotally mounted upon said carrier and means on the frame and actuated by said key for engaging.

the pawl with the teeth of said pinion and then rotating with the pinion at either case shift position of the carriage;

3- The combination with a typewritingmachine having a carriage arranged for letterspace travel upon a case-shift carriage-frame,

and a carriage-feeding mechanism mounted I upon said shift-frame andoperatively con nected to said carriage to control the st'epby-step movement thereof, said carriagefeeding mechanism includinga pinion on the case-shift frame and a rack on said carriage loomeshing with said-pinion, of pinion-rotating means wholly mounted upon the case-shift frame for back-spacing the carriage, said means including a carrier and a pawl ointly operative to'eifect a backward rotation of th'e pinioii, and key-actuated mechanism hav ing a one-way connection operative toengage the pawl at either case-shift position of the carriage.

The combination with a typewriting ma chine including a case-shift frame, a carriage arranged for letter-space travel thereupon, and a carriage-feeding mechanism operatively connected to said carriage to control the step-by-step movement thereof, said carriagefeeding mechanism including a pinion on the case-shift frame and a rack on said carriage meshing with said pinion, of means for backspacing the carriage, said means including a carrier and a pawl mounted upon said pinion and cooperating to rotate the pinion in a re verse direction by first rotating about the pinion and then rotating with the pinion to back-space the carriage;

5. 1 he combination with a typewriting machine including a case-shift frame, a carriage arranged for letter-space travel thereupon, and a carriage-feeding mechanismoperatively on said carrier, means for resiliently hold-' ing the pawl out of engagement with the teeth of said pinion, a sliding member, means for operatively connecting said pawl with the sliding member, said sllding member belng operatively connected to a key, said lastmentioned connections including a key-lever rockably mounted on a stud fast to the side frame of the machine, means for laterally positioning said key-lever and for resiliently holding itin its normal position, a rearward ly-extending arm on said lever, and means for moving said sliding member in a manner to afford the rocking of the pawl toengage with the teeth of the pinion and to swing the carrier on which the pawl is mounted so as to rotate the pinion therewith.

13. The combination with a typewriting machine having a case-shiftable carriage and an escapement-mechanism therefor, said mechanism including a pinion-and-rack arrangement designed to be shifted with the carriage, of means for back-spacing the carriage, said means including a carrier rotatably mounted upon said pinion,- means for yieldingly positioning said carrier, a pawl pivotally mounted on said carrier, means for holding the pawl out of engagement with the teeth of said pinion, a sliding member, means operatively connecting said pawl with the sliding member, said sliding member being operatively connected to a keyelever rockably mounted on a stud fast to the side frame of the machine, means for laterally positioning said key-lever and for yieldingly hold ing it in its normal position, 'a rearwardlyextending arm on said lever, and means for connecting said arm with said sliding member to-eifect the rocking of the pawl to engage with the teeth of the pinion and then swing the carrier and the pawl to rotate the pinion therewith, said sliding member including an upright arm forming an integral part thereof, and a stud on said pawl engaging with said arm, whereby a one-way connection is'eitected between the arm and the stud regardless of the case-shift position of the carriage.

14. The combination with a typewriting machine having a traveling carriage provided with a letter-space feeding mechanism including a rack and a pinion, of an annular rotatable back-spacing unit on the periphery of the pinion and having means co-operative therewith to effect a reverse feed of the cargo when rotated, and means yieldingly l'tlLtlllllllg said unit on said pinion. I

' The combination with a typewriting machine having a traveling carriage provided with a letter-space feeding mechanism includinga rack and a pinion, of an annular rotatable back-spacing unit on the periphery of the pinion and having means co-operative therewith to effect a reverse feed of the carriage when rotated, means yieldingly retaining said unit on said pinion, and key-actuated means on the frame operatively connected to rotate said unit.

16. The combination with atypewriting machine having a traveling carriage provided with a letter-space feeding mechanism including a rack and a pinion, of an annular rotatable back-spacing unit on the periphery of the pinion and having means co-operative therewith to effect a reverse feed of the carriage when rotated, a spring operative toyiel-dingly retain said unit on said pinion and restore said unit to a normal position, and key-actuated means slidable on the frame and operative to rotate said unit in a back-spacing direction against the tension of said spring.

17. The combination with a typewriting machine having a traveling carriage provided with a letter-space feeding mechanism including a rack and a pinion, of an annular rotatable back-spacing unit to rotate upon the periphery of the pinion and having means co-operative with the pinion to effect a reverse feed of the carriage, and a spring operative to yieldingly position the unit upon the pinion.

18. The combination with a typewriting machine having a traveling carriage provided with a letter-space feeding mechanism including a rack and a pinion, of an annular rotatable back-spacing unit including a carrier to rotate upon the periphery of the pinion and having a pawl engageable with the pinion to effect a reverse feed of the carriage, and a restoring spring connected to the carrier that is also operative to yieldingly position the carrier upon the pinion.

19; The combination with a typewriting machine having a letter-space feeding; mechanism including a rack and a pinion, of a back spacing unit assembled upon the pinion in eluding a carrier rotatable upon the pinion, and a pawl rotatable with the carrier and co-- operative with the pinion to effect a reverse feed of the carriage.

' 20. The combination with a typewriting machine having a case-shiftable traveling carriage provided with a letter-space feeding mechanism including a rack and a pinion, of a back-spacing unit assembled to rotate upon the pinion and havingmeans co-operative' Ill] ' iasee a ,thelzewith, to effect a reverse feed of the cars 'iage upon rotation ofthe unit, and key-actu- V atedlneans on the franie disconnected from taet with one part ofthe unit and operative to unifo nilyvihrate the unit ateit her ease shift position of the carriage. a

22. The comblnatlon with atypewriting machine having a oase-shiftahle traveling ear 'iage provided With a lettei space feeding mechanism including araek and a pinion, of a back-spacing unit assembled to rotate upon the pinion and having means (to-operative therewith; to effect a reverse feed of the carriage upon rotation of 1 the unit, and a keyl actuated slide on the frame having an upright extension openative to abut and vibrate the same part ofrtheunit at different casershift positions of, the carriage.

WILLIAM enson. 

